Circular open hearth melting furnace



July 1s, 1952 Filed Sept. 1'7, 1949 H. C. WHISTON CIRCULAR OPEN HEARTHMELTING FURNACE 5 Sheets-Sheet 1 INVENTOR.

HOWARD C. WHISTON.

BY M, Mae/M ATTDRNE YS.

July 15, 1952 H. c. wHlsToN 2,603,476

CIRCULAR OPEN HEARTH MEL-'FING FURNACE Filed Sept. 17, 1949 3Sheets-Sheet 2 JNVENTOR. HOWARD C.WH|STON.

ATTORNEYS.

July 15, 1952 H. c. wHlsToN 2,603,476

` CIRCULAR OPEN HEARTH MELTING FURNACE Filed Sept. 17, 1949 5Sheets-Sheet 5 INVENTOR. A -HowARo c. wHlsToN.

ATTORNEYS.

d ll Miel Patented July 15, 1952 Howard C. Whiston, Clairton, Pa."

Application This invention relates, `as indicated, to an openhearthfurnace, andrv more particularly,- to an open-hearth `furnace 'ofcircular shape having parts which provide -improvements from thestandpoint of charging, production, and construction.

In conventional practice, open-hearthfurnaces are commonly elongatedrectangular structures having end wallsqand side Walls supported bybuckstays bound together by stays and tie rods.

-The Aopen-hearth :bath is--of rectangular shape positioned centrally'ofi the furnace which is provided withreduced throats 'at its open endsproviding .gas portsconnecting the furnace with a complicated brick`Achecker-Work arrangement or regeneratoi' whichrecovers heat from theexhaust gases. Slag'pockets .are formed at the base of the regeneratorstructure in the ends of the furnace. Cold air and gas is admitted atone end of the furnace, burned in the furnace, and the products ofcombustion are exhausted at the other end." The gasgproducts ofcombustion being exhaustedlfrom the r'other end of the furnace by reasonofthe necessity of reversing the flow of lthe products of .combustionthrough the furnace. Another ,clisadvantageof such furnaces is the factthat the slag Ytends to build up on the surface of the metal .bathadjacent the end of the furnace .from whichv the products of combustionare being exhausted, this surface slag operating as an insulatingblanket interfering with the refining of the metal in the bath.Moreover, upon reversal of the .flow of products of combustion throughthe furnace, the slag contained in the pocket at theend of the furnacethrough which the gases vwere being exhausted is chilled and solidifiedby the relatively cold air contacting therewith. f

One of the principalobjects of this invention is to provide animprovedform of open-hearth .furnace which will reduce the rvarearequired for a'furnace of a given refining/capacity, which willseptember 17, 1949, serialNo. 116,340 1o Cnims. (ci. ,zeep- 34) 2l Yeliminate the necessity of reversing the flow of products of combustionthrough the furnace, which will eliminate the formation of an insulatingblanket `of vslag on the Ysurface of the bath within thefurnace, whichwill eliminate the chilling of slag in a pocket at the base of thechamber through ywhich the exhaust gases are vconducted, and Vwhich willsimplify and reduce the cost of construction of the furnace. 'Iothese'and related ends, the open-hearth fur'nacebf this in" vention iscircular-in shape and provides an annular or ring-shaped'trough for'containing'the bath of metal to be refined. The products of combustionare fed to the furnace 'inla direction generally tangenti'ally.` of thecontainerV or trough holding the metal to berened and arel exhausteddownwardly througha flue opening positioned centrally of the.trough..The combi-nedl action of the burners in'feed'in'g .the'gasestangentially to the furnace and of the central exhaust flue iseffective to move the products of lcombustion aroundV the furnace in acirculanhelical or toroidal pathin a manner to be described. Themovement `of the gas in'this .manner causes them to scrub the surfacevof the metal being refined to thereby prevent an accumulation .of slagon the surface of the metal which would .be eective to interfere withthe refining of -`the metal in the bath;V In addition, a heat4 transferdevice is located in thefexhaust passage or flueforithe furnace and is`operativetogcontinuouslytransfer heat to air being :fed to the furnaceand the necessity of reversing the fiow'of gas through .the furnace 'iseliminated. -The top ofV theV furnace is Vremovable so that the'fur-nacemay be chargedl with material fromabovelrather than through openings inthe side aswheretofore vnecessary in conventional open-hearthfurnaces.

Other objects and advantages ofthe invention will becomeapparentfromfthe following description. A y n In the drawings there isshown a-preferred ernbodimentofA the invention. In this showing:

Fig. 1 isl a vertical sectional View of an openhearth furnaceconstructed in raccordance with i the principlesof this invention; l

Fig. 2 is a fragmentary sectional view of apart of the structureshown-in .I ig.,v 1 illustrating in section a stopper VVstructure; forclosing r.the exhaust flue opening when the furnace is being charged;r A4 y Fig. 3 Ais a sectional view `taxen substantially along the linesAIII-III of Fig. 1; and.

Fig. 4 is a'topplan view. Y

Inthe drawings, the --numeral'l designates'an `transversely extendingtie rods and channels.

an annular trough or chamber 8 for holding a bath of metal 9 to berefined. The walls 3 and 4 and the base 2 are so formed that the bottomportion of the trough 8 has an approximately semi-circular surface inany vertical diametrical plane of the furnace. By giving the base of thetrough 8 this shape, the maximum pressure of the metal in the bathagainst the walls 3 and 4 is maintainedV at a minimum. It is thuspossible to reinforce the side walls 3 with circular straps I therebyeliminating the stays and tie rods. or channels heretofore required forsupporting buckstays in position on conventional furnace structures. Theinside of the walls 3 and 4 adjacent to the bath, 9 may also be slopedor have any desired contour. vThe structure thus far described will befound to lessen the cost of construction of an open-hearth furnace ascompared to conventional rectangular furnaces having end and side.buckstays supported Vin position by In addition, the circular shape ofthe trough 8 provides 'a surface on the molten bath which is relativelylong for a given furnace area. The cost of constructing the furnace isthereby materially reduced. VThe furnace parts 2 through 9 arefabricatedv from refractory material and cooling pipes (not shown) maybe provided therein where necessary.

The furnace is provided with a removable roof Y, II of circular shapecomprising a circular Ydisk of refractory material I2 supported fromroof members (not shown) extending transversely of reinforcing rings I3.fiat supported typeas shown or. may be of selfsupporting archeddomeconstruction. This roof may be quickly removed and replaced whennecessary thus savingvaluable refining time in a mannernot possibleVwith present conventional furnaces.

The reinforcing Arings I3 are supported on bracket members I4 mounted atspaced points around the edge of the furnace. Jack screws I5 areprovided for initially jackingV the cover II upwardly with respect tothe furnace I. The roof II may then be removed from the furnace by acrane lto` render its interior accessible for placingV therein a chargeto be refined. When the roof I I is removed from the furnace forcharging, a stopper member I6 is lowered into position the brackets I4and is providedwith a plurality of downwardly extending air supplyconduitsv I8 connected at their lower ends with burner nozzles I9extending through the side wallsY 3 and terminating at positionsadjacent the inner surface of the side wall 3. As best shown in Fig. 3,the nozzles I 9 project angularly into the furnace for The roof II maybe either a delivering products of combustion into the furnace in adirection which may be described as being generally tangentialof Vthetrough 8. More specifically, each of the nozzles I9 project in adirection which is tangential to a circle lying between the walls 3 and4 but closer to the wall 4 than to the wall 3 as shown in Fig. 3. Fuel,solid, liquid, or gas, is supplied to the burner nozzles I9 throughoutconduits 20 connected with a circular fuel supply'bustle 2| mounted onthe supports I4. Valves 22 are provided for adjusting the fuel flow feedto the burner nozzles I9 through the conduits 20. A damper 23 isprovided in each of the air supply conduits I8 for adjusting thequantity of air fed therethrough. The burners may be operated with orwithout additional oxygen or compressed air together with any standardtype of fuel-air ratio control to obtain the proper refining flame.

By reason of the tangential direction in which the angularly positionednozzles I9 feed a combustible mixture of gases to the furnace 8,'itwil1be seen that the burning products of combustion will be moved about thesurface of .thev trough 8 in a generally circular'path. That is, Vtheburning products of combustion will move toward the inner surface of theouter side wall 3 and will be deflected by and moved around the furnacein a circular path about such inner surface. Referring to Fig. 3, itwill be noted that the extended axis of each of the burner nozzles I9intersects withthe outer side wall adjacent the next succeeding burnernozzle. By locating the nozzles in this manner, gas forced out of one ofthe burner nozzles will pick up and impel burning gases from theprevious burner nozzle around the furnace. That is, the action of eachof the nozzles I9 tends to keep the burning products of combustionalready in the furnace moving in a circular path. f

As explained above, Vthe products of combustion are exhausted from thefurnace downwardly through the circular flue opening 1. By exhaustingthe products (3f-combustion in this manner, thegases tendlto rotatein acircular path ina clockwise direction as indicated by the arrows in Fig.1 as theymove in a circular path in a clockwise direction as .indicatedbythe arrows'in Fig. 3. If desired, the-gases vmay also be directed in acounterclockwise path andthe burner nozzles I9 may be set at any angledesired by the furnace operator. The products of combustion thus tend tomove in each of two different circular'paths, and thus will move in acircular helical or toroidal path around ther trough 8. The burningproducts of combustion will thus scrub all points on the surface of thebath 9 in the trough 8, and slag will be prevented from building up onany given area of the surface of the metal in the bath 9. Accordingly,it will be apparent .that this action will be effective to'prevent theformationl of an insulating blanket of slag onthe surface of the metalbath which would otherwise be effective to interfere with therefining ofthe metal in the bath.

In order to'accelerate the renement of the metal in the bath 9, a4plurality of air nozzles or tuyres 25 are provided for blowingcompressed air into the bath. The tuyres 25, in accordance withconventional practice, may be provided ,with water cooling pipes. Asillustrated, the nozzles 25 project angularly downwardly and areconnected with conduits 26 which supply air to the nozzles 25 from acircular bustle 21 mounted on supporting members 28 positioned about theperiphery of the furnace. The provision of the metal from the furnace.

la Bessemer effect, and will cooperate with the action of the nozzlesv[fito accelerate the refining of the metal `in the bath. A mixture ofcompressed air V and 'oxygenjor any other desirable gases, liquids,lorfso li ds;, with or without air may be blown in through the nozzles ortuyres 25.Y i y The furnace .is provided with one or more ports oropenings 30 communicating :with the` `lowermost portion of the trough 8for tapping 'refined One or more openings 3|l are provided at an uppervlevel for the surface of the metal nozzles V2? gives or ports tappingoff 'slagv from in the furnace.

Although the furnace 'is charged from the top after removal of the coverIl asiexplained above, openings 32 are formed in the side walls 3through which molten metal or .other materials may .be charged into thefurnacev Vas required without removal of thefto'p Il or requiringstoppage of the refining operation ofthemetal in the bath. v l

As best shown in Fig. l, the'vertically d0wnwardly extending flue 1connects at its base with a cross passage 34 which isconnectedwith anexhaust stack 35 having a damper 3S therein for controlling `the drafton the furnace.' The transverse passage 311i is provided with ,adepressed portion 37 providing a pocket at the base of the flue 1 in4which molten slag maycollect. "l'rhe I molten slag may be tapped offfrom the depressed portion or pocket 31 as required throughV anysuitable opening (not shown).

As shown in Figs. 3 and 4.the lbustle Il .is

provided with a downwardlyextending connection 39 to an air supplyconduit 4S, having a conu nection with a heat transfer unit orrecuperator indicated as a whole` and diagrammatically by the numeral4i. The .recuperator llll may be any suitable heat transfer structureadapted to absorb heat from the products of combusti-on passing throughthe passage 34 and Vfortransferring such heat to air being delivered tothe conduit 40. Since this invention is not concerned per se with thestructure of the recuperator 4| `and any suitable heat transfer devicemay be employed for its purpose, the structure of the recuperator il hasbeen illustrated diagrammatically only. An opening 38 is provided in thetransverse passage 34 for the reception Iof the heat transfer. unit lli.The ,numerals i2 and 43 respectively indicate diagrammatically a fan`and operating lmotor therefore for forcing airto be heated through therecuperator 4|. The recuperator di delivers heated air to the conduit 40which delivers the heated air through the connection 39 to. the bustleI1. From the bustle I1,.the heated air is fed to the nozzles, I9 asexplained above...A In this arrangement, it will 4hefnoted that heatedair is fed continuously to the bustle il without any complicatedreversing process as required in conventional open-hearth furnaces. Inthis manner,

.the products of combustion flow. continuously through the exhaust flue'Land slag collecting in the pocket 31 is never chilled by beingsubjected to ablast of relatively cold vair passing over the surfacethereof. The slag in the pocket 31 is thus maintained in a moltencondition and may be 'tapped off at any timev during the operation ofthe furnace. The furnace may also beY constructed Vand operated ifvdesired without the use of-the recuperator 4l and the fan '42.' Theburner nozzles i9 may also be any type of fuel burners now used inevery-day practice.

From the foregoing, it Will be apparent that 6 this invention provides anovel form vof circular open-hearth furnace having therein an annulartrough for containing the metal bath to be refined. Attention isparticularly directed to the fact that the novel cooperationt of theburners in feeding a mixture of combustible 'gas in adirectiontangentially of the trough @with the centrally located flue 'liseffective to' move the products of combustion over the surfaceof themetal bath in a toroidal path. Theentire surface of the metal bath isthus subjected to a scrubbing action by the products of combustion tofacilitate andexpedite the refining 'of the metal in the bath. Attentionis also particularly directed to the fact that the provision of anannular trough 8 provides a trough of considerable length within acomparatively small area'as compared to the area required foropen-hearth furnaces of conventional construction, and the cost ofconstructing a furnace having a givenv capacity is reduced in comparisonto conventional open-hearth furnaces. Attention is further directed tothe factl tration, and that various'changes'and modificaf tions may bemade therein Withinthe ccnte1n plation of my invention and vunder-thescope of the following claims. l u" Y* y I claim: 1 v i. In anopen-hearthfurnace, the combination comprising a circular trough 'for'containing a l bath of metal to be refined, a 'fuel-burner' forlintroducing burning gases "into Vthe furnace in a direction generallytangential to a circle lying between the edges of the trough, and anexhaust fiue positioned centralfly'of said 'troughfor exhausting thegases from the furnace in a vertical- 1y ydownward direction, the motionimparted to the gases by said burner and said flue being effective toswirl the gases aroundthe trough in a toroidal path to thereby subjectthe surface of the metal bath in thev trough to a scrubbing actionbysaid gases.

2. En ran open-hearth furnace, the combination comprising acircularfurnace base having a circular side wall about 'its periphery and acircular elevated projection at its center but of 'less .height than thewall and an opening centrally'of said projection, said side wall andprojection cooperating to define a circular trough for containing a bathof metal to be refined a plurality of burners atspaced intervals aboutthe furnace for introducing burning gases in a 'direction generallytangentialto a circle lying between the edges of the trough, and 'anexhaust Hue in cornl munication with saidl projection opening from thebase of the furnacesaidburners and flue having a combinedactioneifectiveto -move the burn' irljsf gases in a toroidal path over'theVsurface of vthe metal bath insaid trough fout of rthetrough by thescrubbing action ofthe products oi' `combustion on the 14 surface of themetalbatnV f 4. In :an open-hearth furnace, -thecombination comprising acircular .furnace base lhaving' a circular side Wall about its peripheryand a circular elevated projection at its center -but of less heightthan the wall and an opening centrally of said projection, said sideWall-and projection cooperatingvtoedefine an approximately circulartrough for containing abath of metal to be refined, an exhaust flue incommunication with and extendingin a downward direction from saidprojectionV opening, a roof mounted for removal from the furnace torender said trough accessible from above for quickly charging thefurnace with metal to be refined, and a stopper for mounting temporarilyon said projection to cover said opening and prevent metal being chargedinto said trough from` entering said fiue.

5. In an open-hearth furnace, the combination comprisingra circularfurnace base having a circular side wall about its periphery and acircular elevated projection at its center and an opening centrally ofsaid projection, said side wall and projection cooperating to define acircular trough for containing a bath of metal to be refined, theportion of said base defining the bottom of said trough having a surfacewith a semi-circular shape in any plane extending transversely of saidprojection and side walls, an exhaust fiue in communication with andextending in a downward direction from said projection opening, burnermeans for subjecting the surface of the bath to the action of burningproducts of combustion to thereby provide an open-hearth refiningaction, and a plurality of tuyres respectively projecting at a radialand downward angle with respect to said trough for introducing air,gases, or any fluid or solid into the bath to provide an additionalrefining action of the Bessemer type.

6. In an open-hearth furnace, the combination comprising a circularfurnace base having a circular side wall about its periphery and acircular elevated projection at its center but of less height than thewall and an opening centrally of said projection, said side wall andprojection cooperating to define a circular trough for containing a bath'of metal to be refined, a plurality of burners at spaced intervalsabout the furnace for introducing burning gases in a Vdirectiongenerally tangential to a circle lying between the edges of the trough,an exhaust fiue in communication with and extending in a downwarddirection from said projection opening, said burners and flue having acombined action effective to move f the burning gases in a toroidal pathover the surface of the metal bath in said trough, a roof mounted forremoval from the furnace to render said trough accessible from above forcharging the furnace with metal -to be refined, and a stopper formounting temporarily on said projection to cover said opening andprevent metal being charged into said trough from'entering said fiue.

7. In an open-hearth furnace, the combination comprising a circularfurnace base having a circular side wall about its periphery and acircular trough within said sidewall for containing f a bath of metal tobe refined, a fuel burner for introducing burning gases into the furnacein a direction generally tangential to a circle lying between the edgesof the trough, and an exhaust Vfiue positioned centrally of said troughfor exhausting the lgases from the furnace in a vertically downwarddirection, the motion .imparted to the gases by said burner and saidflue being effective to swirl the gases around thetrough in a toroidalpath to thereby subject the surface of `tliemetal bath in the trough toa scrubbing 8. `In an open-hearth furnace, the combination comprising acircular furnace base having a circular side wall about its peripheryand a circular trough within said side wall for containing a bath ofmetal to be refined, a fuel burner for introducing burning gases intothe furnace in a direction generally tangential to a circle lyingbetween the edges of the trough, and an exhaust flue positionedcentrally of said trough for exhausting the gases from the furnace in avertically downward direction, the motion imparted to the gases by saidburner and said fiue being effective to swirl the gases around thetrough in a toroidal path to thereby subject the surface of the Vmetalbath in the trough to a scrubbing action by said gases, a roof mountedon said side wall for removal from the furnace to render said troughaccessible from above for quickly charging the furnace with metal to berefined, and a stopper for temporarily covering said exhaust ue toprevent metal being charged into the trough from entering the fiue.

9. In an open-hearth furnace, the combination comprising a circularfurnace base having a oircular side wall about its periphery and acircular trough within said side wall for containing a bath of metal tobe refined, a fuel Iburner for introducing burning gases into thefurnace in a direction generally tangential to a circle lying betweenthe edges of the trough, and an exhaust flue positioned centrallyv ofsaid trough for exhausting the gases from the furnace in a verticallydownward direction, the motion imparted to the gases by said burner andsaid flue being effective to swirl the gases around the trough in atoroidal path to thereby subject the surface of the metal bath in thetrough to a scrubbing action by said gases, and a stopper for mountingtemporarily on said exhaust flue to prevent metal being charged into thetrough from entering the flue.

10. In an open-hearth furnace, the combination comprising a circularfurnace base having a circular side wall about its periphery and acircular elevated projection at itsv center but of less height than thewall and an opening centrally of said projection, said side wall andprojection cooperating to define a circular trough for containing a bathof metal to be refined, a plurality of burners atspaced intervals aboutthe furnace for introducing burning gases in a direction such that saidgases move in a generallyhorizontal annular path above said trough, andan exhaust flue in communication with said projection opening forexhausting thel gases from the furnace in a vertically downwarddirection.

HOWARD Ci. WHISTON.

REFERENCES CITE The following references areof record in the file ofthis patent:

Y UNITED STTES PA'IENTS Number Nissim Oct. 9, 1945

